TY - CONF A1 - Hüsken, Götz A1 - Brouwers, H.J.H. T1 - The influence of the fines on the early-age behavior of zero-slump concrete T2 - 18. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2012-09-12 KW - Zero-slump concrete KW - Green-strength KW - Compaction behavior KW - Intensive compaction test PY - 2012 SN - 978-3-00-034075-8 VL - 2 IS - 3.07 SP - 2-0001 - 2-0008 AN - OPUS4-26541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercia, G. A1 - Spiesz, P. A1 - Hüsken, Götz A1 - Brouwers, H.J.H. T1 - Chloride intrusion and freeze-thaw resistance of self-compacting concrete with two different nano-SiO2 T2 - 18. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2012-09-12 KW - Nano-SiO2 KW - Concrete KW - Self compacting KW - Durability KW - Chloride and freeze-thaw KW - Nano-silica PY - 2012 SN - 978-3-00-034075-8 VL - 2 IS - 3.07 SP - 2-0123 - 2-0136 AN - OPUS4-26542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babski, Veronika A1 - Hüsken, Götz A1 - Pirskawetz, Stephan A1 - Ehlers, Noah A1 - Kühne, Hans-Carsten A1 - Brouwers, H.J.H. ED - Fehling, E. ED - Middendorf, B. ED - Thiemicke, J. T1 - Characterisation of Ultra-High Performance Fibre Reinforced Concrete (UHPFC) under tensile loading by acoustic emission and optical deformation analysis N2 - During the past 20 years, innovative developments in concrete technology have enabled the production of ultra-high performance fibre reinforced concretes (UHPFC) for the protection and preservation of concrete structures. The main characteristics of UHPFC comprise high compressive and flexural strength as well as high ductility compared to normal strength, normal weight concrete (NSC). This paper focuses on the analysis of crack formation and crack propagation in UHPFC under tensile loading under quasistatic conditions by using acoustic emission (AE) and optical deformation analysis (ODA). AE is a non-destructive technique to monitor the development of micro structural damage processes caused by external forces. In this context, AE allows for a continuous monitoring of changes in the microstructure (cracks) over time and the corresponding localisation by appropriate algorithms. The AE measurements were performed along with ODA at the surface of the samples in order to analyse the deformation behaviour of the samples and the crack propagation. For the tests, a UHPFC reference mixture was developed and tested with three different volume percentages of steel fibres (1.0 V.-%, 2.0 V.-%, and 3.0 V.-%). This paper shows that the application of AE is a suitable method to analyse the crack propagation in UHPFC specimens under tensile loading and to localise the crack initiation. Furthermore, insights into the failure mechanism of the fibres are offered by the analysis of the signals of the AE measurements, which allows for a better understanding of UHPFC and its general performance. T2 - 4th International Symposium on Ultra-High Performance Concrete and High Performance Materials (HiPerMat) CY - Kassel, Germany DA - 09.03.2016 KW - UHPFC KW - Tensile loading KW - Acoustic emission KW - Crack formation KW - Optical deformation analysis KW - Crack propagation PY - 2016 SN - 978-3-7376-0094-1 SP - 1 EP - 9 PB - Kassel University Press CY - Kassel AN - OPUS4-36893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercia, G. A1 - Hüsken, Götz A1 - Brouwers, H.J.H. T1 - Effect of olivine nano-silica additions on the fresh and hardened behaviour of cement pastes and mortars N2 - The high demand for sustainable and durable building materials requires profound knowledge on the material properties. In this respect, the phenomena occurring at nano-level are of crucial importance for the design of new building materials. Therefore, all around the world, increasing amounts of funding are being directed to research projects dealing with material properties on nano-level, which is claimed to have tremendous potential for the future. One of the most referred to and used cementitious nano-material is amorphous silica with a particle size in the nano-range, even though its application and effects on concrete have not been fully understood yet. Olivine (Mg,Fe)2Si04 is the fastest weathering siiicate mineral dissolving easily in acid. Düring dissolution in acid the metallic ions (Mg2+,Fe2+) are replaced by H+, yielding Si(OH)4 monomers and metallic ions in solution. After cleaning treatments an amorphous nano-silica is obtained. The produced olivine nano-silica (OnS) has a specific surface area between 100 and 400 m2/g, the size of the primary particles, which are agglomerated in Clusters, ranges from 10 to 25 nm and the impurity content is below 5 % IV. Literature related with the application of OnS in cement based materials is scarce; only one research work performed by Justnes and Ostnor 121 is available. Thus, the effect of adding OnS in cement based Systems has been not studied. Based on this, the present research aims on elucidating the effects of OnS in the fresh and hardened state of cement pastes and mortars. T2 - 1st International conference on the chemistry of construction materials CY - Berlin, Germany DA - 07.10.2013 KW - Nano-silica KW - Self compacting concrete KW - Durability KW - Chloride KW - Freeze-thaw PY - 2013 SN - 978-3-936028-75-1 SP - 179 EP - 182 AN - OPUS4-30410 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -